NASA Technical Memorandum 100158

.

I SINDA-NASTRAN Interfacing Program Theoretical Description

~ and User's Manual

Steven R. Winegar Lewis Research Center Cleveland, Ohio

August 1987

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(liASA-T?I-100158) S I N D A - N A S S R A T XYTERPACIIG 1587-27268 FEOGB1M 3HEOBETICAL DESCRIETICY AND USER'S H l l l U h E ( N A S A ) 2 1 p A v a i l : H I S EiC AO3/HP A01 CSCL 20K U n c l a s

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SINDA-NASTRAN INTERFACING PROGRAM THEORETICAL DESCRIPTION AND U S E R ' S MANUAL

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Steven R. W i negar N a t i o n a l Aeronaut ics and Space A d m i n i s t r a t i o n

Lewis Research Center Cleveland, Oh io 44135

SUMMARY

S t dard p r a c t i c e i n a n a l y z i n g thermal deformat ions or s t r e s s e s i n a

a program such as SINDA (Systems Improved Numerical D i f f e r e n c i n g Ana lyze r ) , t o p r e d i c t temperatures i n t h e s t r u c t u r e , and g e n e r a t i o n o f f i n i t e e lement s t r u c - t u r a l models, u s i n g a program such as M W N A S T R A N (NAsa STRuctural ANa lys i s ) , t o p r e d i c t thermal deformat ions and s t resses i n the s t r u c t u r e . The t a s k o f c o n v e r t i n g SINDA model temperature r e s u l t s i n t o NASTRAN model thermal loads can be v e r y l a b o r i n t e n s i v e i f the re i s n o t one node-to-one e lement , or system- a t i c node-to-element, c o r r e l a t i o n between models.

s t r u c t u Y e o f t e n e n t a i l s g e n e r a t i o n o f f i n i t e d i f f e r e n c e thermal models, u s i n g

T h i s paper desc r ibes t h e SINDA-NASTRAN I n t e r f a c i n g Program ( S N I P ) , a FORTRAN computer code t h a t generates NASTRAN s t r u c t u r a l model thermal l oad cards g i v e n S I N D A (or s i m i l a r thermal model) temperature r e s u l t s and thermal model geometr ic da ta . S N I P generates thermal l o a d cards f o r NASTRAN p l a t e , s h e l l , ba r , and beam elements.

The paper desc r ibes t h e i n t e r f a c i n g procedures used by S N I P . S N I P uses a geomet r ic search r o u t i n e and a numer ica l cod ing scheme t o r e l a t e thermal model nodes t o s t r u c t u r a l model e lements. S N I P then c a l c u l a t e s element tempera tures based on the weighted average o f temperatures o f the thermal nodes r e l a t e d t o each e lement . User c o n t r o l l e d i n p u t parameters p r o v i d e c o n t r o l o v e r node-to- e lement c o r r e l a t i o n .

Sec t i ons on program s e t up and o p e r a t i o n d i scuss t h e mechanics o f s e t t i n g up and r u n n i n g t h e program. I n p u t parameters and i n p u t f i l e s a re desc r ibed . I n t e r p r e t a t i o n o f o u t p u t f i l e r e s u l t s i s d iscussed.

Sample cases a re i n c l u d e d t o demonstrate use of t h e program and show i t s ' performance under a v a r i e t y o f c o n d i t i o n s . S N I P can p r o v i d e s t r u c t u r a l model thermal loads t h a t a c c u r a t e l y r e f l e c t thermal model r e s u l t s w h i l e r e d u c i n g t h e t i m e r e q u i r e d t o i n t e r f a c e thermal and s t r u c t u r a l models when compared t o o t h e r methods.

INTRODUCTION

P r e d i c t i n g thermal d i s t o r t i o n s and thermal s t r e s s e s i n a s t r u c t u r e r e q u i r e s the g e n e r a t i o n o f b o t h thermal and s t r u c t u r a l models o f t h e s t r u c t u r e under c o n s i d e r a t i o n . Standard p r a c t i c e o f t e n e n t a i l s g e n e r a t i o n o f f i n i t e d i f - f e rence thermal models, u s i n g a program such as SINDA (Systems Improved Numeri- c a l D i f f e r e n c i n g Ana lyze r ) , to p r e d i c t temperatures i n t h e s t r u c t u r e , and g e n e r a t i o n o f f i n i t e element s t r u c t u r a l models, u s i n g a program such as MSC/ NASTRAN (NAsa STRuctural ANa lys i s ) , to p r e d i c t thermal de fo rma t ions and s t r e s - s e s i n the s t r u c t u r e .

D i f f i c u l t y may a r i s e , however, i n c o n v e r t i n g thermal model tempera ture r e s u l t s i n t o s t r u c t u r a l model thermal loads f o r l a r g e models. The t a s k o f r e l a t i n g s p e c i f i c thermal nodes t o s p e c i f i c s t r u c t u r a l e lements can be v e r y l a b o r i n t e n s i v e i f t h e r e i s n o t one node-to-one e lement , or sys temat i c node-to- e lement , c o r r e l a t i o n between models.

Th i s paper descr ibes t h e SINDA-NASTRAN I n t e r f a c i n g Program ( S N I P ) . S N I P i s a FORTRAN computer program t h a t generates NASTRAN s t r u c t u r a l model thermal loads from thermal model tempera ture r e s u l t s . S N I P c o r r e l a t e s thermal nodes t o s t r u c t u r a l elements t o i n t e r f a c e S I N D A (or s i m i l a r ) f i n i t e d i f f e r e n c e t h e r - mal models w i t h NASTRAN f i n i t e element s t r u c t u r a l models made up o f p l a t e , s h e l l , b a r , and beam elements. Node-to-element c o r r e l a t i o n i n c l u d e s de je rmin- i n g which S I N D A nodes shou ld be r e l a t e d t o each NASTRAN element and c a l c u l a t - i n g a w e i g h t i n g factor for temperatures a s s o c i a t e d w i t h each e lemen t - re la ted thermal node.

S N I P uses thermal model geometry, i n f o r m a t i o n t h a t must be combined w i t h s tandard thermal model tempera ture r e s u l t s , and s t r u c t u r a l model geometry, i n f o r m a t i o n t h a t i s a v a i l a b l e from s tandard NASTRAN i n p u t , to search th rough th ree-d imens iona l space around each s t r u c t u r a l e lement f o r t h e neares t thermal nodes. Thermal and s t r u c t u r a l models must b o t h be d e f i n e d i n t h e same, s i n g l e C a r t e s i a n coo rd ina te system. The thermal nodes l o c a t e d neares t each e lement a r e used t o determine e lement tempera ture f o r thermal d i s t o r t i o n and s t r e s s a n a l y s i s . Shaping and u s e r - c o n t r o l l e d s i z i n g o f the th ree-d imens iona l search r e g i o n , a l o n g w i t h numer ica l cod ing of thermal node and s t r u c t u r a l e lement num- b e r s , p r o v i d e f o r s e p a r a t i o n o f s u b s t r u c t u r e s d u r i n g c o r r e l a t i o n .

S N I P can p rov ide s t r u c t u r a l model thermal loads t h a t a c c u r a t e l y r e f l e c t thermal model r e s u l t s w h i l e reduc ing the t ime r e q u i r e d t o i n t e r f a c e therma and s t r u c t u r a l models when compared t o o t h e r methods.

D E S C R I P T I O N

Use o f S N I P r e q u i r e s t h e g e n e r a t i o n o f SINDA (or s i m i l a r thermal ana- Note t h a t good dea l y z e r ) and NASTRAN models o f t h e hardware under s tudy .

c o o r d i n a t i o n i s r e q u i r e d between a n a l y s t s g e n e r a t i n g t h e two models. of

I n p u t t o the program i s a f i l e o f thermal model tempera ture r e s u l t s and p h y s i c a l l o c a t i o n o f each thermal node i n th ree-d imens iona l space, combined i n a SNIP-unique fo rmat . The thermal node p h y s i c a l l o c a t i o n d a t a r e q u i r e d by S N I P i s n o t a s tandard thermal model o u t p u t , and must be genera ted i ndependen t l y . I f tempera ture g rad ien ts e x i s t th rough t h e s t r u c t u r a l e lements (de termined per - haps by t h e use of m u l t i p l e thermal nodes i n t h e thermal model ) , t he g r a d i e n t s must be c a l c u l a t e d p r i o r t o i n p u t t o S N I P as g r a d i e n t s a t s p e c i f i c thermal node l o c a t i o n s . Note t h a t i n o r d e r t o de termine t h e proper s i g n and o r i e n t a t i o n o f tempera ture g r a d i e n t s i n the s t r u c t u r a l e lements the thermal a n a l y s t must be f a m i l i a r w i t h the s t r u c t u r a l model geometry.

Also i n p u t t o S N I P i s a s tandard NASTRAN i n p u t deck f o r a model made up o f p l a t e , s h e l l , beam and ba r e lements. and CBEAM elements of NASTRAN. source code by the user , c o n t r o l t he node-to-element c o r r e l a t i o n .

S N I P suppor ts t h e C T R I A , CQUAD, CBAR, I n p u t parameters, a d j u s t e d i n t h e program

I 2

SINDA-NASTRAN I n t e r f a c i n g Program ( S N I P ) i s , to some degree, a misnomer. Though t h e program was o r i g i n a l l y w r i t t e n t o use S I N D A tempera ture r e s u l t s , tempera ture d a t a from any source can now be used as l o n g as i t i s en te red i n t h e c o r r e c t , SNIP-unique format .

For NASTRAN p l a t e and s h e l l elements S N I P searches th rough t h r e e - d imens iona l space to f i n d t h e thermal nodes neares t each element i n each o f f o u r quadrants i n the e lement p lane. searches th rough th ree-d imens iona l space t o f i n d t h e thermal nodes neares t each e lement end ( g r i d p o i n t ) i n each o f t h e two d i r e c t i o n s a l o n g the element a x i s . The d i s t a n c e from an element, or element end, t o each o f t h e neares t thermal nodes i s used to determine a w e i g h t i n g f a c t o r for temperatures a t those nodes.

For NASTRAN ba r and beam elements S N I P

Ou tpu t from S N I P a re NASTRAN element tempera ture l o a d cards f o r each e l e - ment and NASTRAN case c o n t r o l cards for each tempera ture l oad s e t . Also o u t - p u t by S N I P i s a l i s t o f e lements w i t h t h e numbers o f t h e SINDA nodes r e l a t e d t o each element, and t h e we igh t g iven each node i n tempera ture c a l c u l a t i o n s .

PROGRAM PROCEDURES

The program uses a combina t ion o f techn iques t o r e l a t e thermal nodes t o s t r u c t u r a l e lements. The p r i m a r y technique i s t o search i n space fo r t h e nodes l o c a t e d neares t each e lement . However, s ince c l o s e l y spaced nodes a re n o t n e c e s s a r i l y r e l a t e d ( t h e y may be nodes o f two c l o s e l y spaced, b u t separa te , p a r t s o f a s t r u c t u r e ) , a techn ique to shape and reduce t h e th ree-d imens iona l search r e g i o n i s used. The reduced, shaped search r e g i o n s a r e c a l l e d " q u a l i f i - c a t i o n " r e g i o n s and have a c h a r a c t e r i s t i c shape fo r each element t y p e . I n a d d i t i o n t o q u a l i f i c a t i o n r e g i o n s , a numer ica l cod ing scheme p r o v i d e s f o r keep- i n g node-to-element c o r r e l a t i o n i n o r d e r .

Every SINDA ( t h e r - ma l ) node i s checked a g a i n s t each NASTRAN element f o r c o r r e l a t i o n . node and element numbers a r e coded to a l l o w a c o r r e l a t i o n , t hen t h e geomet r ic search r o u t i n e i s employed t o determine whether a thermal node i s w i t h i n the e lement q u a l i f i c a t i o n r e g i o n and whether t h e thermal node i s t he neares t node i n t h e r e g i o n segment. Once node-element c o r r e l a t i o n has been de termined f o r eve ry element a w e i g h t i n g scheme i s used t o c a l c u l a t e element tempera tures from thermal node temperatures. Q u a l i f i c a t i o n r e g i o n s , numer ica l cod ing o f

The c o r r e l a t i o n r o u t i n e log ic i s d e p i c t e d i n f i g u r e 1. I f t h e

thermal node numbers and s t r u c t u r a l element numbers, and the w e i g h t i n g scheme a re desc r ibed below.

Q u a l i f i c a t i o n Regions

tempera ture

Q u a l i f i c a t i o n r e g i o n s d e f i n e the shape and s i z e o f t h e pace i n whi h t h e program w i l l search around an element f o r thermal nodes. Thermal nodes o u t - s i d e t h e q u a l i f i c a t i o n r e g i o n for an element a re cons idered too f a r from t h e e lement t o be u s e f u l i n c a l c u l a t i n g i t s tempera ture . Q u a l i f i c a t i o n r e g i o n s d i f f e r for d i f f e r e n t element types ( i . e . , p l a t e and s h e l l e lement q u a l i f i c a - t i o n r e g i o n s a re shaped d i f f e r e n t l y t han bar and beam element q u a l i f i c a t i o n r e g i o n ) .

3

For p l a t e and s h e l l e lements, t h e o b j e c t i v e o f t h e c o r r e l a t i o n i s t o de termine t h e average tempera ture of, and t h e tempera ture g r a d i e n t t h rough , each e lement , t o be o u t p u t on a NASTRAN T E M P P l l o a d c a r d f o r each e lement ( r e f . 1 ) . Thermal nodes may c a r r y some thermal g r a d i e n t da ta , which must have t h e c o r r e c t s i g n wi th r e s p e c t t o t h e p l a t e or s h e l l e lements to which t h e nodes w i l l be r e l a t e d .

Q u a l i f i c a t i o n r e g i o n s f o r p l a t e and s h e l l e lements ( f i g . 2 ) a r e d i s c - shaped r e g i o n s centered a t t he e lement c e n t r o i d . The c e n t r a l p l a n e o f the disc-shaped r e g i o n i s t h e p lane d e f i n e d by the element c e n t r o i d and t h e f i rs t two co rne rs ( s t r u c t u r a l nodes) l i s t e d on the NASTRAN e lement c o n n e c t i v i t y c a r d f o r t h e e lement . The d i s c i s separa ted i n t o fou r quadrants ( q u a l i f i c a t i o n r e g i o n segments) us ing t h e e lement c o o r d i n a t e s y s t e m . The n e a r e s t thermal node i n each reg ion quadrant i s determined d u r i n g the search o p e r a t i o n and any empty r e g i o n quadrant i s no ted .

The r a d i u s and th i ckness of t h e q u a l i f i c a t i o n reg ions a r e t h e same for a l l p l a t e and s h e l l e lements, and a r e s e t up by user a d j u s t a b l e program i n p u t parameters. Parameter ALWDR i n t h e program s e t s the r a d i u s and parameter ALWDTH s e t s t h e h a l f - t h i c k n e s s o f t h e search r e g i o n .

For bar and beam elements the o b j e c t i v e of t h e c o r r e l a t i o n i s t o d e t e r - mine t h e average temperature o f , and tempera ture g r a d i e n t s i n t h e e lement Y and Z d i r e c t i o n s ( f i g . 3 ) o f , each end o f each bar and beam element , t o be o u t p u t on a NASTRAN TEMPRB l o a d c a r d f o r each element ( r e f . 1 ) . i n p u t as thermal node d a t a must have the correct s i g n w i t h r e s p e c t to the b a r or beam elements t o which t h e nodes w i l l be r e l a t e d .

Grad ien ts

Q u a l i f i c a t i o n r e g i o n s fo r ba r and beam elements ( f i g . 4) a r e box-shaped r e g i o n s , one for each end o f t h e element, cen tered a t t h e c e n t r o i d o f t h e e l e - ment end. One s i d e o f the box-shaped r e g i o n i s p a r a l l e l t o the e lement X-ax is . Each box i s separa ted i n t o two ha lves ( q u a l i f i c a t i o n r e g i o n segments) a t t h e end o f the e lement . The neares t node i n each h a l f i s found d u r i n g t h e search o p e r a t i o n and any empty h a l f i s no ted .

The X, Y, and Z d imensions o f the box-shaped q u a l i f i c a t i o n r e g i o n s a r e the same f o r bo th ends o f a l l ba r and beam elements, and a r e s e t up by program i n p u t parameters. Parameters ALWDR2, ALWDY, and ALWDZ s e t t he h a l f - s i z e o f t h e search r e g i o n i n t h e e lement X, Y, and Z d i r e c t i o n s r e s p e c t i v e l y .

Q u a l i f i c a t i o n r e g i o n s a l l o w t h e a n a l y s t t o s i z e t h e search r e g i o n for a l l e lements. However, t h e r e i s s t i l l p o t e n t i a l for tempera ture d a t a from a t h e r - mal node meant t o be r e l a t e d t o one p a r t o f a s t r u c t u r e t o be used to d e t e r - mine tempera ture o f a d i f f e r e n t p a r t o f t h e s t r u c t u r e . For example, a p l a t e s t r u c t u r e supported by back ing r i b s t i f f e n e r s may lead t o o v e r l a p p i n g q u a l i f i - c a t i o n r e g i o n s ( f i g . 5 ) . Should a thermal node l i e i n t h e ove r lapped r e g i o n i t may be r e l a t e d to b o t h a p l a t e e lement and a ba r element by t h e program. Th is s i t u a t i o n does n o t c r e a t e a problem i f no tempera ture g r a d i e n t d a t a i s passed from SINDA and t h e nodal tempera ture da ta i s r u l y meant t o be used fo r b o t h t h e sur face and back ing s t r u c t u r e . However, i f t h e node i s s p e c i f i c a l l y t o be r e l a t e d on ly t o p l a t e or o n l y t o ba r elements c a r r y i n g a p p r o p r i a t e t e m - p e r a t u r e g r a d i e n t da ta ) a p o t e n t i a l p rob lem e x i s t s . Numerical cod ing can a l l e - v i a t e t h i s problem.

4

Numer i c a l Cod i ng

Numer ica l cod ing i s t he use o f thermal node numbers and s t r u c t u r a l e l e - ment numbers t o separa te subs t ruc tu res . A p p r o p r i a t e numbering o f thermal nodes i n i n p u t d a t a and s t r u c t u r a l elements i n t h e i n p u t NASTRAN model i d e n t i - f i e s s u b s t r u c t u r e s . If thermal nodes a re n o t numbered f o r c o r r e l a t i o n w i t h a p a r t i c u l a r e lement , S N I P w i l l n o t determine t h e thermal nodes p h y s i c a l (geomet- r i c ) r e l a t i o n t o t h e element t o cons ider t h e node for c o r r e l a t i o n .

Numerical cod ing of i n p u t thermal model node numbers and NASTRAN element numbers i s d e p i c t e d i n f i g u r e 6. Four i n p u t parameters, N V A R l , NVAR2, NVAR3, and NVAR4 c o n t r o l t h e cod ing o p e r a t i o n . SINDA nodes numbered above NVARl a r e r e l a t e d o n l y t o p l a t e and s h e l l elements numbered above NVAR2. Nodes numbered below NVARl a r e r e l a t e d o n l y t o p l a t e and s h e l l e lements numbered below NVAR2. S INDA nodes numbered below NVAR3 are r e l a t e d o n l y t o ba r and beam elements num- bered below NVAR4. Nodes numbered above NVAR3 a r e r e l a t e d o n l y t o bar and beam elements numbered above NVAR4. The cod ing scheme a l l o w s t h e a n a l y s t t o separa te s u b s t r u c t u r e s from each o the r f o r c o r r e l a t i o n .

One p o t e n t i a l way to separa te the s u p p o r t i n g beam s t r u c t u r e from a p l a t e s t r u c t u r e i s d e p i c t e d i n f i g u r e 7 . F i r s t , number a l l p l a t e e lements be low NVARZ and a l l s u p p o r t i n g beam s t r u c t u r e e lements above NVAR4. Second, s e t NVARl and NVAR3 equa l . T h i r d , number SINDA nodes for and nodes f o r t h e beams above NVAR3. Th i s w i l l r e s u l o f t h e back ing and s u r f a c e s t r u c t u r e s ( f i g . 8) d u r i n g

O v e r a l l , t h e numer ica l cod ing scheme and t h e qua techn ique combine t o g i v e t h e ana lys t good c o n t r o l o f c o r r e l a t i o n .

t h e p l a t e s below NVARl i n complete s e p a r a t i o n

c o r r e 1 a t i o n .

i f i c a t i o n r e g i o n search t h e node t o element

Weight ing Scheme

Once the a p p r o p r i a t e thermal nodes have been found for each s t r u c t u r a l e lement , and t h e c h a r a c t e r i s t i c d is tances for each node de termined, a we igh t - i n g f a c t o r for each node r e l a t e d t o each e lement i s c a l c u l a t e d . i s t i c d i s t a n c e s a re element c e n t r o i d t o thermal node l o c a t i o n for p l a t e and s h e l l elements, and c e n t r o i d o f element end t o thermal node l o c a t i o n f o r each end o f ba r and beam elements.

The c h a r a c t e r -

The fo rmu la used to c a l c u l a t e w e i g h t i n g f a c t o r s i s :

X w e i g h t i n g factorNode - - - 1

where

R, i s t h e c h a r a c t e r i s t i c d i s tance for node x , one o f t h e nodes r e l a t e d to t h e element under c o n s i d e r a t i o n

R j i s t he c h a r a c t e r i s t i c d i s tance for node i, each o f t h e nodes r e l a t e d t o t h e e 1 emen t under cons i d e r a t i o n

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N i s t h e number o f nodes r e l a t e d to an e lement or e lement end (= number of q u a l i f i c a t i o n r e g i o n segments)

N = 4 f o r p l a t e s and s h e l l s ; N = 2 f o r ends o f ba rs and beams. The sum of t h e nodal weights for each element or element end i s 1.0. r e g i o n segments i n which no c o r r e l a t i n g thermal node i s found, t h e R i t o an imaginary node 0 i s s e t v e r y l a r g e so t h a t t h e w e i g h t i n g f a c t o r f o r t h e node i s approx imate ly 0.0. The d e f a u l t c h a r a c t e r i s t i c d i s t a n c e i f no thermal node i s found i s s e t by parameter XLARGE, which must be t h r e e o r d e r s of magnitude l a r g e r than t h e l a r g e s t c h a r a c t e r i s t i c d i s t a n c e . Th is i s v a r i a - b l e i n o r d e r t o avo id machine memory problems t h a t may be encountered when work ing w i t h a v a r i e t y o f machines.

The NASTRAN i n p u t f i l e must c o n t a i n a s tandard NASTRAN i n p u t deck i n t h e s i n g l e f i e l d format. A l l g r i d p o i n t d e f i n i t i o n and element c o n n e c t i v i t y must be done w i t h separate, e x p l i c i t cards ( i . e . , column d u p l i c a t i o n and g e n e r a t i o n commands cannot be used) . On ly p l a t e , s h e l l , beam, and ba r elements (CTRIA3, CTRIA6, CQUADA4, CQUAD8, CBEAM, and CBAR) can have tempera ture l o a d cards gen- e r a t e d by S N I P . A lso , columns one and t e n o f t h e cards must have t h e i r charac- t e r f i e l d s l e f t j u s t i f i e d .

For q u a l i f i c a t i o n d i s t a n c e

S N I P p laces some f u r t h e r requ i rements on t h e thermal and NASTRAN models. The NASTRAN model must be d e f i n e d i n a s i n g l e C a r t e s i a n c o o r d i n a t e sys tem. I n a d d i t i o n , t he thermal model r e s u l t s must be desc r ibed i n t h e same s i n g l e Car te - s i a n c o o r d i n a t e s y s t e m .

t h e program code, and can be changed t h e r e by t h e a n a l y s t . dev i ce number for t h e NASTRAN i n p u t deck, I N S I N D A i s t h e d e v i c e number o f f o r t h e S I N D A i n p u t f i l e , and I S C R T C H l , ISCRTCH2, ISCRTCH3, and IGRDHLD a r e s c r a t c h f i l e s f o r i n te rmed ia te d a t a s to rage .

I n p u t and o u t p u t da ta dev i ce numbers a re d e f i n e d i n t h e d a t a s e c t i o n o f NASTDECK i s t h e

Output F i l e s

Outputs i n c l u d e a f i l e o f NASTRAN case c o n t r o l cards , a f i l e o f NASTRAN tempera ture load cards , and a f i l e o f node-element c o r r e l a t i o n i n f o r m a t i o n . Reference 1 descr ibes use o f t h e NASTRAN case c o n t r o l and tempera ture l o a d ca rds . The case c o n t r o l f i l e ho lds a subcase card , a l a b e l card , and a temper- a t u r e l o a d s e t number ca rd f o r each thermal l o a d subcase. Up t o 10 thermal l o a d subcases can be processed by the program i n a s i n g l e r u n . The tempera- t u r e l o a d ca rd f i l e ho lds temperature l o a d cards f o r each e lement f o r each case. TEMPPl cards a re f o r p l a t e or s h e l l elements and TEMPRB cards a r e f o r bar or beam elements. The c o r r e l a t i o n i n f o r m a t i o n f i l e ( f i g . 9) l i s t s each s t r u c t u r a l element by element t ype . I t l i s t s t h e thermal nodes r e l a t e d to each e lement , and the we igh t g i v e n temperature and temperature g r a d i e n t s a t each node for each element.

IOCHECK i s t h e dev i ce number o f t h e o u t p u t f i l e o f node-element c o r r e l a - t i o n and we igh t i ng f a c t o r s t o be checked by t h e a n a l y s t . dev i ce number of t h e o u t p u t f i l e o f NASTRAN case c o n t r o l ca rds , and INASTEMP i s t h e dev i ce number o f t h e o u t p u t f i l e of NASTRAN tempera ture l o a d ca rds .

INASSUB i s t h e

R e s u l t s o f t h e w e i g h t i n g f a c t o r c a l c u l a t i o n s a r e used t o we igh t tempera- t u r e s c a l c u l a t e d for an element or element end as:

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N = (W.F.)Node i * ( tempera ture INode i=l

Temperature element or end o f e l e m e n t

where

Node i a r e the nodes r e l a t e d t o the element under c o n s i d e r a t i o n

W.F. i s t h e w e i g h t i n g f a c t o r

N i s t h e number of nodes r e l a t e d to an e lement or element end ( = number o f q u a l i f i c a t i o n r e g i o n segments)

N = 4 for p l a t e or s h e l l e lements; N = 2 f o r bar o r beam element ends. same e q u a t i o n i s used t o c a l c u l a t e element tempera ture g r a d i e n t s , w i t h tempera- t u r e g r a d i e n t s u b s t i t u t e d for temperature i n the equa t ion .

The

A t a b l e o f the NASTRAN elements w i t h t h e r e l a t e d S I N D A nodes and t h e w e i g h t i n g f a c t o r s for those SINDA nodes i s o u t p u t for t h e a n a l y s t t o check ( f i g . 9). A warn ing message i s inc luded f o r any e lement for which no thermal nodes w e r e found i n the c o r r e l a t i o n r o u t i n e . Th is f i l e shows e x p l i c i t l y t h e node-element r e l a t i o n s h i p s used by S N I P t o genera te NASTRAN thermal l o a d cards .

PROGRAM OPERATION

Use o f S N I P r e q u i r e s t h e genera t i on o f S I N D A , or s i m i l a r t he rma l , and NASTRAN models o f t h e hardware under s tudy . C o o r d i n a t i o n i s r e q u i r e d between t h e a n a l y s t s g e n e r a t i n g the two models. Adjustment o f i n p u t parameters i n t h e S N I P source code a l l o w s the S N I P ana lys t t o c o n t r o l t h e node-to-element c o r r e - l a t i o n per formed by the program. l o a d cards o f each thermal l o a d case, case c o n t r o l ca rds for each case, and a t a b l e o f node-element c o r r e l a t i o n and assoc ia ted w e i g h t i n g f a c t o r s .

The o u t p u t o f S N I P a r e s e t o f temperature

Inpu t Parameters

I n p u t parameters a r e used t o c o n t r o l node-to-element c o r r e l a t i o n as des- c r i b e d i n PROGRAM PROCEDURES. Two a d d i t i o n a l parameters, I D I M I and IDIM2, d imension t h e a r r a y s used i n S N I P . ments depending on problem s i z e (problem s i z e i s l i m i t e d on t h e P C ) . s e t s t h e dimensions on most NASTRAN-related a r r a y s , and shou ld be s e t equal t o t h e l a r g e r o f t h e number o f NASTRAN g r i d p o i n t s and t h e number o f NASTRAN e l e - ments i n t h e i n p u t NASTRAN f i l e . IDIM2 s e t s t h e d imensions on most thermal mode l - re la ted a r r a y s , and shou ld be s e t equal t o t h e number o f thermal nodes i n t h e i n p u t thermal model r e s u l t s f i l e .

These a l l o w f o r changing memory r e q u i r e - I D I M I

To change the parameters one must change t h e parameter s e t t i n g s i n the PARAMETER s tatements o f t he S N I P source code and recomp i le t h e source code. Program comments i n the code descr ibe each parameter . Appendix A shows the v a r i a b l e s and parameters l i s t s i n the comments s e c t i o n o f t h e S N I P source f i l e and shows t h e f i r s t 35 l i n e s o f t h e S N I P program. The f irst 35 l i n e s c o n t a i n a l l program PARAMETER and DATA s tatements.

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I n p u t F i l e s

I n p u t s t o t h e program i n c l u d e a f i l e o f thermal model tempera ture r e s u l t s i n a SNIP-unique fo rmat , and a s tandard NASTRAN i n p u t deck i n t h e s i n g l e f i e l d f o r m a t .

The thermal model r e s u l t s i n p u t f i l e must c o n t a i n , for each case, t h e r u n t i t l e , a t i m e assoc ia ted w i t h t h e r e s u l t s , t h e number o f node d a t a ca rds for t h e case, and the node d a t a cards . The r u n t i t l e and t i m e a r e used o n l y t o genera te NASTRAN subcase l a b e l s . Node d a t a cards must c o n t a i n , i n o r d e r , t h e thermal node number, average node tempera ture , tempera ture g r a d i e n t i n t h e element Z d i r e c t i o n a t t he node, X, Y, Z c o o r d i n a t e s o f t h e c e n t e r o f t h e node i n space, and temperature g r a d i e n t i n t h e element Y node. be en tered . p e r a t u r e r e s u l t s i n the SNIP-unique i n p u t f o r m a t . mine tempera ture g r a d i e n t s i n t h e element Y and Z d i r e c t i o n s t h e thermal a n a l y s t must be f a m i l i a r w i t h t h e s t r u c t u r a l model geometry. F i g u r e 10 shows the S I N D A r e s u l t s i n p u t f i l e and fo rmats r e q u i r e d by SNIP .

d i r e c t i o n a t t h e For nodes w i t h no assoc ia ted tempera ture g r a d i e n t s a 0.0 g r a d i e n t must

A t present no s tandard SINDA s u b r o u t i n e e x i s t s t h a t produces tem- Note t h a t i n o r d e r t o d e t e r -

SAMPLE CASES

Four sample cases show v a r i o u s f e a t u r e s o f S N I P and i t s o p e r a t i o n . Case 1 shows t h e b a s i c o p e r a t i o n o f t h e program fo r a s imp le tempera ture p a t t e r n i n a s t r u c t u r e . Case 2 shows t h e r e s u l t s o f program o p e r a t i o n for a f a i r l y complex tempera ture p a t t e r n . Cases 3 demonstrates use o f cod ing to separa te subs t ruc - t u r e s . Case 4 demonstrates us o f q u a l i f i c a t i o n r e g i o n s to separa te s u b s t r u c t u r e s .

Case 1 . - Bas ic Performance for a Simple Temperature P a t t e r n

Case 1 shows S N I P performance fo r a s imp le tempera ture p a t t e r n i n a s t r u c - t u r e . Case 1 cons is t s of a square p l a t e under a u n i f o r m tempera ture g r a d i e n t across the p l a t e , from corne r t o co rne r . F i g u r e 1 1 shows t h e NASTRAN g r i d , a s imp le 10 by 10 g r i d o f square 1 by 1 i n . e lements. F i g u r e 12 shows t h e SINDA node l a y o u t on the p l a t e . The l o c a t i o n s o f t h e S I N D A nodes a re t h e i r p h y s i c a l c e n t e r s ( i . e . , node 1 i s l o c a t e d a t x = 1.67 i n . , y = 1.67 i n . , z = 0.0 i n . ) .

Table I i s the thermal model r e s u l t s i n p u t f i l e for t h e tempera ture p a t - t e r n o f f i g u r e 13. There a re no temperature g r a d i e n t s th rough t h e p l a t e for Case 1. The r e l e v a n t i n p u t parameters fo r Case 1 a r e : ALWDR = 10 i n . , ALWDTH = 0.01 i n . , XLARGE = 1 xlO5 i n . , NVARl = 500, WAR2 = 500, NVAR3 = 500, NVAR4 = 500. F i g u r e 14 shows t h e temperatures o f the s t r u c t u r a l e lements, as ca l cu - l a t e d by SNIP. One would expec t elements a l o n g l i n e s p a r a l l e l to a l i n e from t h e upper le f t -hand corner a t element 91 t o t h e lower r i g h t - h a n d co rne r a t e l e - ment 10 t o have approx imate ly equal temperatures c a l c u l a t e d by S N I P . S N I P c a l - c u l a t e s 75" temperatures for elements 10, 19, 28, 37, 46, 55, 64, 73, 82, and 91, as expected. A l i n e from element 61 to element 7 shou ld show a n e a r l y con- s t a n t temperature s i g h t l y g r e a t e r than 50"and does. a long a l i n e from element 2 to 100, as expected. S N I P produces a good tempera- t u r e p a t t e r n i n the s t r u c t u r a l model, r e p r e s e n t a t i v e o f t h e tempera ture pa t - t e r n f r o m t h e thermal model r e s u l t s f o r Case 1 .

S N I P genera tes a g r a d i e n t

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F i g u r e 15 d e p i c t s t h e p h y s i c a l node-element r e l a t i o n s h i p s f o r e lement number 21 i n Case 1. Q u a l i f i c a t i o n r e g i o n segment 1 c o n t a i n s nodes 4 t o 9. Node 4 i s t h e c l o s e s t of those i n segment 1 and, t h e r e f o r e , i s t h e node used for e lement temperature c a l c u l a t i o n . S i m i l a r l y , o n l y node 1 , o f nodes 1 t o 3, wh ich a l l l i e i n segment 4 , i s used for element tempera ture c a l c u l a t i o n . R 1 and R4 are the c h a r a c t e r i s t i c d i s tances from element 21 t o t h e nodes i n seg- ments 1 and 4 r e s p e c t i v e l y . No nodes a r e found i n segments 2 and 3, and so R 2 and R 3 t o an imag inary node 0 a r e s e t equal t o parameter XLARGE. Note t h a t node 1 i s c l o s e r t o element 21 t h a n node 4 , and i s , t h e r e f o r e , g i v e n more we igh t i n element temperature c a l c u l a t i o n ( t a b l e 11).

s i d e r e d i n t h e search r o u t i n e performed fo r each element. I f ALWDR had been s e t s m a l l e r , 2.2 i n . for example, o n l y c l o s e l y l o c a t e d nodes would have been used f o r temperature c a l c u l a t i o n a t each e lement . Table I 1 shows t h e node- element c o r r e l a t i o n and w e i g h t i n g f a c t o r s f o r some e lements w i t h ALWDR = 10 i n . f o r Case 1 . Table I11 shows the node-element c o r r e l a t i o n and w e i g h t i n g f a c - t o r s f o r the same elements w i t h ALWDR = 2.2 i n . f o r Case 1 . F i g u r e 16 shows t h e temperatures o f t h e s t r u c t u r a l elements c a l c u l a t e d by S N I P f o r Case 1 w i t h ALWDR = 2.2 i n . The r e s u l t f o r a small ALWDR i s t h a t tempera ture c a l c u l a t i o n s a r e dominated by t h e nodes near each e lement .

Note t h a t ALWDR i s s e t l a r g e i n Case 1 so a l l thermal nodes w i l l be con-

Case 2. - Performance f o r a Complex Temperature P a t t e r n

Case 2 demonstrates S N I P performance for a complex tempera ture p a t t e r n i n a s t r u c t u r e . Case 2 c o n s i s t s o f t h e same s t r u c t u r e and thermal nodes as Case 1 under a un ique temperature p a t t e r n . F i g u r e 17 shows t h e tempera ture p a t t e r n o f t h e thermal model f o r Case 2. The p a t t e r n rep resen ts a case w i t h a hea t source a t node 6 and a heat s i n k a t node 4 . t h e same as fo r Case 1 , w i t h ALWDR = 10 i n .

I n p u t parameters f o r Case 2 a re

F i g u r e 18 shows the temperatures of t h e s t r u c t u r a l e lements as c a l c u l a t e d by S N I P for Case 2 . and n e a r l y cons tan t temperatures s l i g h t l y g r e a t e r than 50" from element 6 t o element 96. F i g u r e 19 shows what c o u l d be cons ide red i so the rma l l i n e s based on t h e thermal model i n p u t . F i g u r e s 18 and 19 a r e c o n s i s t e n t . The Case 2 r e s u l t s show t h a t S N I P can genera te reasonab le tempera ture p a t t e r n s i n a s t r u c t u r a l model for complex i n p u t t empera tu re p a t - t e r n s .

One would expect a cons tan t tempera ture l i n e a t x = 5 i n . ,

S N I P generates expected r e s u l t s .

Case 3 . - Use of Coding t o Separate Subs t ruc tu res

Case 3 shows how cod ing can be used t o separate s u b s t r u c t u r e . Case 3 adds to the s t r u c t u r e o f Case 1 and 2 a l i n e of bar elements a l o n g y = 5 i n . , o f f s e t from the p l a t e 0.5 i n . i n t h e +Z d i r e c t i o n ( f i g . 20 ) . S N I P i n p u t thermal nodes 1001, 1002, and 1003 r e p r e s e n t the bar s t r u c t u r e and a r e cen- t e r e d 0.5 i n . above nodes 4 , 5, and 6, r e s p e c t i v e l y . F i g u r e 21 shows t h e t h e r - mal model temperature p a t t e r n . I n p u t parameters fo r Case 3 a r e t h e same as those for Case1 and 2 w i t h t h e a d d i t i o n t h a t ALWDR2 = 10 i n . , ALWDY = 0.5 i n . , and ALWDZ = 1 i n . ALWDZ i s purpose ly s e t l a r g e enough t o emcompass some p l a t e thermal nodes.

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Parameters NVAR1, NVAR2, NVAR3, and NVAR4 a r e a l l s e t equal to 500, which a l l o w s t h e numbering o f t h e ba r e lements and t h e b a r thermal nodes t o com- p l e t e l y separa te t h e b a r and p l a t e s t r u c t u r e s d u r i n g node-to-element c o r r e l a - t i o n . As a r e s u l t thermal nodes 1001 t o 1003 a r e r e l a t e d only to e lement 501 t o 510, and thermal nodes 1 t o 9 a r e o n l y r e l a t e d t o e lements 1 to 100 i n t h e c o r r e l a t i o n scheme, though some nodes l i e i n o v e r l a p p i n g q u a l i f i c a t i o n r e g i o n s f o r Case 3. The temperatures a l o n g t h e ba r s t r u c t u r e , as c a l c u l a t e d by S N I P , a re : e lement 501 ( x = 0 i n . end) = -20", e lement 503 ( x = 2 i n . end) = -15", e lement 505 ( x = 4 i n . end) = 15", e lement 507 ( x = 6 i n . end) = 45", e lement 509 ( x = 8 i n . end) = 75" . and element 510 ( x = 10 i n . end) = 80". The o u t p u t tempera ture p a t t e r n o f t h e p l a t e i s i d e n t i c a l t o t h a t of Case 2 , as expected.

The temperature cards genera ted by S N I P for Case 3 a c c u r a t e l y r e f l e c t t h e thermal model r e s u l t s f e d t o t h e program.

Case 4 . - Use o f Q u a l i f i c a t i o n Regions t o Separate Subs t ruc tu res

Case 4 demonstrates how q u a l i f i c a t i o n r e g i o n s can be used to separa te sub-

+Z d i r e c t i o n s t r u c t u r e s . Case 4 adds to t h e s t r u c t u r e of Case 3 a second l i n e o f b a r e l e - ments a l o n g y = 4 i n . , o f f s e t from the p l a t e 0.5 i n . i n the ( f i g . 22) . S N I P i n p u t thermal nodes 1011 to 1013 r e p r e s e n t t h i s a d d i t i o n a l back ing s t r u c t u r e . 1012-(5, 4 , 0.5 i n . ) , and 1013-(10, 4 , 0.5 i n . ) . Temperature i n p u t d a t a a r e the same as Case 3 w i t h the a d d i t i o n o f temperatures for nodes 1011, 1012, and 1013 which a r e -15, 35, 85" r e s p e c t i v e l y . I n p u t parameters f o r Case 4 a r e t h e same as those for Case 3. Note t h a t ALWDY = 0.5 i n .

Loca t ions o f the nodes a r e 1011-(0, 4 , and 0.5 i n . ) ,

F i g u r e 23 dep ic t s the q u a l i f i c a t i o n r e g i o n o f t h e x = 2 i n . end o f e l e - ment 512. Note t h a t , because o f t h e s i z e and shape t h e r e g i o n , t h e p o t e n t i a l problem o f u s i n g tempera ture d a t a from node 1001 for c a l c u l a t i o n o f the temper- a t u r e o f t h e x = 2 i n . end o f element 512 i s p rec luded . Temperature d a t a from thermal node 1011 i s used a t t h e x = 2 i n . end o f element 512 even though t h e r - mal node 1001 i s p h y s i c a l l y c l o s e r . Table 4 shows t h a t thermal nodes 1001, t o 1003 a r e r e l a t e d o n l y t o elements 501 to 510, and thermal nodes 1011 t o 1013 a re r e l a t e d o n l y t o elements 511 to 520 by the c o r r e l a t i o n r o u t i n e . Table 5 shows t h e r e s u l t i n g temperatures i n the beam s t r u c t u r e s for Case 4.

correspond t o the g l o b a l X , Y, and Z d i r e c t i o n s i n t h i s example. ALWDR2, ALWDY, and ALWDZ a r e t h e h a l f - s i z e s o f t h e box-shaped q u a l i f i c a t i o n r e g i o n i n the element coo rd ina te system ( f i g s . 2 and 3 ) .

One n o t e o f c a u t i o n : The ba r element X , Y, and Z d i r e c t i a n s happen t o

PROBLEM SETUP / RESULTS INTERPRETATION / OPERATING PROCEDURES

The a n a l y s t faces d e t e r m i n a t i o n o f q u a l i f i c a t i o n r e g i o n s i z e s and cho ice o f a s u b s t r u c t u r e s e p a r a t i o n method ( q u a l i f i c a t i o n r e g i o n s w i t h or w i t h o u t numer ica l cod ing) when s e t t i n g up a S N I P r u n .

The spac ing between thermal nodes must be cons idered i n s i z i n g t h e q u a l i - f i c a t i o n r e g i o n s . Case 1 r e s u l t s above show t h a t s i z i n g q u a l i f i c a t i o n r e g i o n s l a r g e enough t o envelope nodes i n most or a l l o f t h e r e g i o n segments leads t o smooth g r a d i e n t s i n the tempera ture p a t t e r n across t h e s t r u c t u r a l model. S i z i n g q u a l i f i c a t i o n r e g i o n s sma l l , such t h a t t h e y envelope o n l y t h e nodes

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n e a r e s t an e lement , leads t o a s t r u c t u r a l model tempera ture p a t t e r n t h a t c l e a r l y matches t h e l a y o u t of thermal nodes on t h e s t r u c t u r e , w i t h o u t smooth g r a d i e n t s across t h e e n t i r e s t r u c t u r e . The S N I P a n a l y s t must keep these r e s u l t s i n mind when s i z i n g q u a l i f i c a t i o n r e g i o n s .

The cho ice o f a s u b s t r u c t u r e separa t i on method depends p r i m a r i l y on model geometry. I n t h e case where model geometry i s s imp le enough fo r q u a l i f i c a t i o n r e g i o n s a lone t o keep s u b s t r u c t u r e s separa te ( i . e . , t h e r e i s l i t t l e n t e r t w i n - i n g or c l o s e l y spaced s u b s t r u c t u r e ) cod ing shou ld n o t be used. T h i s a l l o w s complete freedom i n node and element numbering f o r S I N D A and NASTRAN model- e r s . I n t h e case where t h e s t r u c t u r e i s complex ( i . e . , t h e r e i s a s g n i f i c a n t amount o f i n t e r t w i n i n g or c l o s e l y spaced s u b s t r u c t u r e ) cod ing shou ld be used, i n a d d i t i o n t o q u a l i f i c a t i o n reg ions , t o separa te s u b s t r u c t u r e s .

P o t e n t i a l problems t h e S N I P ana lys t f aces i n c l u d e i n a p p r o p r i a t e q u a l i f i c a - t i o n r e g i o n s i z i n g , i n c o n s i s t e n c y between model geomet r ies , and i n c o m p a t i b i l - i t y i n node and element numbering (cod ing) . f i l e p r o v i d e s a warn ing message i f any element i s w i t h o u t any c o r r e l a t a b l e nodes. T h i s f i l e ho lds t h e key t o assu r ing t h a t S N I P i s per fo rming w e l l . Note t h a t i t i s i m p o r t a n t to c a r e f u l l y r e v i e w t h i s f i l e as i t i s t h e p r i m a r y i n d i c a t o r o f how S N I P has per formed.

The S N I P node-element c o r r e l a t i o n

I f many elements have few o r no r e l a t e d thermal nodes, t h e r e i s a p o s s i - b i l i t y o f : (1 ) unders i zed q u a l i f i c a t i o n r e g i o n s , ( 2 ) i n c o n s i s t e n c y between SINDA and NASTRAN model geomet r ies , o r ( 3 ) node and e lement number cod ing i n c o m p a t i b i l i t y . S INDA and NASTRAN modelers to assure geomet r ic cons i s tency and cod ing compati- b i l i t y . The S N I P a n a l y s t must understand bo th models, and unders tand com- p l e t e l y t h e o p e r a t i o n o f SNIP , i n order t o s e t up and c o n t r o l o p e r a t i o n o f S N I P and to p r o v i d e a p p r o p r i a t e guidance t o thermal and s t r u c t u r a l modelers .

The key to good SNIP performance i s good c o o r d i n a t i o n between

I n o r d e r to comp le te l y understand S N I P o p e r a t i o n o f the S N I P a n a l y s t shou ld become f a m i l i a r w i t h t h e source code. The source code c o n t a i n s exten- s i v e comments i n o r d e r t o gu ide t h e user th rough i t s ' o p e r a t i o n .

S N I P i s w r i t t e n i n A N S I standard FORTRAN. Two v e r s i o n s o f t h e program c u r r e n t l y e x i s t . One v e r s i o n runs on a I B M 3270 PC-AT and t h e o t h e r runs on a CRAY X-MP. The o n l y d i f f e r e n c e i n the two programs i s t h a t OPEN s ta tements i n t h e source code o f the PC v e r s i o n per form the f u n c t i o n of ASSIGN s ta tements t h a t must be p r e s e n t i n t h e CRAY job C o n t r o l Statement F i l e when r u n n i n g t h e Cray v e r s i o n ( r e f . 2 ) . Ass ign statements must be i n c l u d e d i n t h e user - s u p p l i e d CRAY C o n t r o l Statements F i l e f o r each S N I P i n p u t and o u t p u t f i l e when t h e CRAY v e r s i o n i s run .

For r u n n i n g t h e PC v e r s i o n t h e NASTRAN i n p u t deck must be i n a f i l e named NASTRAN.CDS, and t h e thermal model r e s u l t s must be i n a f i l e named SINDA.CDS. The PC v e r s i o n w i l l w r i t e temperature l o a d cards i n t o a f i l e named TMPTR.CDS, w i l l w r i t e subcase c o n t r o l cards i n t o a f i l e named SUBCASE.CDS, w i l l w r i t e t h e node-element c o r r e l a t i o n and we igh t ing f a c t o r s l i s t i n t o a f i l e named SNIPIO.CHK. Appendix B i s a S N I P o p e r a t i o n c h e c k l i s t f o r r u n n i n g t h e PC ver - s i o n o f t h e program.

For r u n n i n g t h e CRAY v e r s i o n of S N I P , CRAY Job C o n t r o l Language (JCL) s ta tements must be i n c l u d e d i n the Con t ro l Statements F i l e t o p u t NASTRAN and thermal model i n p u t f i l e s i n t o CRAY f i l e s and ass ign t h e f i l e s t h e a p p r o p r i a t e

11

FORTRAN u n i t number so S N I P can access the f i l e s . NASTRAN i n p u t cards must be i n u n i t NASTDECK, and thermal model i n p u t cards must be i n u n i t I N S I N D A .

CRAY JCL must a l s o name, and a s s i g n a p p r o p r i a t e FORTRAN u n i t numbers to, o u t p u t f i l e s and i n t e r m e d i a t e d a t a s to rage f i l e s . ISCRTCH2, ISCRTCH3, and IGRDHLD must be a v a i l a b l e f o r i n t e r m e d i a t e d a t a stor- age. NASTRAN temperature l o a d cards w i l l be w r i t t e n i n t o u n i t INASTEMP, NASTRAN subcase cards w i l l be w r i t t e n i n t o u n i t INASSUB, and t h e node-element c o r r e l a t i o n and w e i g h t i n g f a c t o r s l i s t w i l l be w r i t t e n i n t o u n i t IOCHECK by S N I P . The FORTRAN u n i t numbers a r e d e f i n e d i n source code d a t a s ta tements , and can be changed t h e r e by t h e a n a l y s t (see appendix A ) . p l e r u n f i l e , i n c l u d i n g CRAY JCL, for r u n n i n g the CRAY v e r s i o n o f S N I P .

FORTRAN u n i t s I S C R T C H l ,

Appendix C i s a sam-

Appendix D i s a S N I P o p e r a t i o n c h e c k l i s t f o r r u n n i n g t h e CRAY v e r s i o n o f the program.

APPLICATIONS

S N I P can be a p p l i e d t o l a r g e thermal and s t r u c t u r a l models (hundreds or thousands o f thermal nodes and s t r u c t u r a l e lements) made up o f p l a t e , s h e l l , ba rs , and beam s t r u c t u r e s . equal t o or f i n e r than the thermal model node mesh. Th is p resumpt ion i s based on thermal model ing l i m i t a t i o n s when c o n s i d e r i n g r a d i a t i v e hea t t r a n s f e r , as one must when ana lyz ing s t r u c t u r e s i n the space env i ronment . A s i t u a t i o n w i t h a thermal node mesh equal t o or g r e a t e r than t h e f i n i t e element mesh i s assumed t o be one i n which one node-to-one element or sys temat ic node-to-element c o r r e - l a t i o n can be exe rc i sed .

Program o p e r a t i o n presumes a NASTRAN e lement mesh

S N I P has been a p p l i e d t o thermal de fo rma t ion a n a l y s i s i n s a t e l l i t e antenna r e f l e c t o r s w i t h good r e s u l t s ( r e f . 3 ) . The t ime r e q u i r e d t o f e e d t h e r - mal a n a l y s i s r e s u l t s to s t r u c t u r a l a n a l y s i s models u s i n g S N I P i s smal l when compared t o o the r methods. One i n d i r e c t advantage o f u s i n g S N I P i s t h e h i g h degree of c o o r d i n a t i o n and communication t h a t takes p lace between thermal and s t r u c t u r a l modelers u s i n g t h i s approach. Th is can l e a d to e a r l y d e t e c t i o n o f errors i n e i t h e r or b o t h models.

S N I P i s c u r r e n t l y i n use f o r a n a l y s i s o f s o l a r c o n c e n t r a t o r s f o r space s o l a r dynamic e l e c t r i c power g e n e r a t i o n systems. Large thermal and s t r u c t u r a l models a r e r e q u i r e d to a c c u r a t e l y p r e d i c t t h e r m a l l y d i s t o r t e d su r face shapes. S N I P i s expected to save a s i g n i f i c a n t amount of t ime and e f f o r t i n combin ing c o n c e n t r a t o r thermal and s t r u c t u r a l model s .

CONCLUDING REMARKS

P o t e n t i a l f u t u r e enhancements t o S N I P i n c l u d e t h e a d d i t i o n of more d iag - n o s t i c messages, change i n the method o f parameter c o n t r o l , au tomat ion o f qua l - i f i c a t i o n r e g i o n s i z i n g , a d d i t i o n o f d i f f e r e n t w e i g h t i n g schemes, a d d i t i o n o f t h e c a p a b i l i t y to use s tandard SINDA o u t p u t , and a d d i t i o n of o t h e r e lement capabi 1 i ty .

More d i a g n o s t i c message c a p a b i l i t y cou ld be added t o t h e program t o i n d i - c a t e p o t e n t i a l problems and s o l u t i o n s . C o n t r o l o f S N I P parameters may be

12

changed from PARAMETER s tatements i n t h e source code t o an i n p u t f i l e , so t h e program need n o t be recomp i led each t ime parameters a r e changed.

SINDA node number cod ing i n f o r m a t i o n and t h e average SINDA node spac ing . c o u l d reduce t h e amount of work r e q u i r e d o f the S N I P a n a l y s t .

schemes c o u l d be added. T h i s would a l l o w more user c o n t r o l o f t h e node- e lement r e l a t i o n s h i p s .

Q u a l i f i c a t i o n r e g i o n s i z i n g cou ld be automated u s i n g a combina t ion o f Th is

A d d i t i o n a l u s e r - c o n t r o l l e d , and perhaps even u s e r - w r i t t e n , w e i g h t i n g

A d d i t i o n o f t h e c a p a b i l i t y t o use s tandard SINDA o u t p u t c o u l d be added. Th is would e l i m i n a t e t h e need f o r r e f o r m a t t i n g SINDA o u t p u t tempera ture r e s u l t s , though thermal model geometr ic d a t a would s t i 1 1 be added s e p a r a t e l y .

F i n a l l y , t h e c a p a b i l i t y to handle a d d i t i o n a l NASTRAN e lements, such as s o l i d elements, c o u l d be added. This would make S N I P a p p l i c a b l e t o a l a r g e r number of t h e r m a l - s t r u c t u r a l problems.

SNIP i s , however, a v e r y powerful a n a l y t i c a l tool as i t stands today. S N I P i s use fu l for combin ing thermal and s t r u c t u r a l a n a l y s i s f o r which t h e r e i s n o t one node-to-one e lement , or sys temat ic node-to-element c o r r e l a t i o n between models. S N I P can p r o v i d e s t r u c t u r a l model thermal loads t h a t accu- r a t e l y r e f l e c t thermal model r e s u l t s th rough t h e use o f a geomet r ic search rou- t i n e and a numer ica l cod ing scheme.

S N I P r e q u i r e s t h e a d d i t i o n o f geometr ic d a t a t o s tandard thermal model r e s u l t s i n o r d e r t o r e l a t e thermal and s t r u c t u r a l models. Though t h e a d d i t i o n of geomet r ic d a t a r e q u i r e s a d d i t i o n a l e f f o r t on t h e p a r t o f the thermal ana- l y s t , t h e o v e r a l l e f f o r t r e q u i r e d t o use S N I P i s , f o r most l a r g e models, s ig - r l i f i c a n t l y s m a l l e r t han t h a t r e q u i r e d t o i n t e r f a c e t h e models manua l l y .

13

APPENDIX A

S N I P S o u r c e Code V a r i a b l e and P a r a m e t e r L i s t s , and PARAMETER and DATA S t a t e m e n t s

C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C

C C C C C C C

.C C C C C C C C C C C C C C C C C C C

-c

-c

1 1 1 1 1 l ~ * l 1 1 1 X * l * I l VARIABLE L I S T I*i**lttlf****i*f**i1* CARDS -ARRAY CONTAINING THE I N P U T NASTRAN CARDS IQUADS -ARRAY CONTAINING F I E L D S 2 THROUGH 7 OF CQUAD4

I T R I A S -ARRAY CONTAINING F I E L D S Z THROUGH 6 OF C T R I A 3

BARS -ARRAY CONTAINING F I E L D S 2 THROUGH 1 0 OF CBAR AND

AND CQUAD8 CARDS FROM NASTRAN

AND C T R I A 6 CARDS FROM NASTRAN

CARDS FROM NASTRAN

I****

CBEAM

IDS -ARRAY CONTAINING THE BEAM AND BAR ELEMENT NUMBERS PLUS -ARRAY CONTAINING F I E L D S 1 AND 4 THROUGH 9 OF CONTINUATION

IGRIDS,GRIDS -ARRAY CONTAINING F I E L D S 2 THROUGH 6 OF G R I D CARDS FROM NASTRAN

CARDS FROM NASTRAN IPTRQ, ITPTRT, IPTRA; IPTRB -POINTER ARRAYS CONTAINING NODE NUMBER

OF SINDA NODES ASSOCIATED WITH EACH QUAD. T R I A . A END. AND B END OF NASTRAN F t F M F N T I -_-..-...-

QFACTOR,TFACTOR,AFACTOR,BFACTOR -ARRAYS CONTAINING WEIGHTING FACTORS ASSOCIATED WITH S I N D A NODES I N POINTER F I L E S ABOVE

CNTROID -X,Y.Z P O S I T I O N OF PLATE AND SHELL ELEMENT CENTROIDS T,DELT -TEMPERATURE AND TEMPERATURE GRADIENT F I L E S FOR P L A T E

VECTl,VECTL,VECT3 -VECTORS USED FOR CHECKING SINDA NODE

r**ff*r**f*f***rrffrr*rr****~r*rr***rr****r*rrr*rr*r**rrrf*rf

AND SHELL ELEMENT TEMPERATURE CALCULATION

Q U A L I F I C A T I O N

NVAR2 - CODING PARAMETER FOR NASTRAN PLATE AND SHELL ELEMENTS NVAR3 - CODING PARAMETER FOR SINDA NODES TO BE RELATED TO

NVARQ - CODING PARAMETER FOR NASTRAN BAR AND BEAM ELEMENTS ALWDR - PLATE AND SHELL ELEMENT Q U A L I F I C A T I O N REGION RADIUS

BAR AND BEAM ELEMENTS

_._. (OF DISC~HAPED REGION) -~ - -

ALWDTH - PLATE AND SHELL ELEMENT Q U A L I F I C A T I O N REGION

ALWDR2, ALWDY, ALWDZ - BAR AND BEAM ELEMENT Q U A L I F I C A T I O N HALF-THICKNESS (OF DISC-SHAPED REGION)

REGION HALF-SIZES I N THE X. Y , AND Z DIRECTIONS RESPECTIVELY

NODE I S FOUND I N A PARTICULAR Q U A L I F I C A T I O N REGION SEGMENT ( T H I S I S V A R I A B L E FOR MACHINE ADAPTATION

XLARGE - DEFAULT RADIUS TO IMAGINARY NODE NUMBER "0" WHEN NO

P I I P P n I F C I . -... ----. I D I M 1 , I D I M Z - ARRAY DIMENSIONING PARAMETERS. THESE ALLOW FOR

CHANGING MEMORY REQUIRMENTS DEPENDING ON PROBLEM S I Z E . I D I M l ' S E T S DIMENSION ON MOST NASTRAN-RELATED ARRAYS. I D I M Z SETS DIMENSION ON SINDA-RELATED ARRAYS.

f*r*f*fiffl**f*1fM****r*rr*r*r****r***r***rr**r**l********rr**ll*

PROGRAM INTRFACE PARAMETER ( N V A R l ~ 2 0 0 ~ N V A R 2 ~ 2 0 0 ~ A L W D R ~ l O ~ ~ A L W D T H ~ . O O l ~

PARAMETER ( A L W D R 2 = 1 0 . , I D I M 2 = 3 0 O r X L A R G E = l . E + 5 ) PARAMETER ~ALWDZ=.5,ALWDY=.5,NVAR3=5OO.NVAR4=5OO,IDIMl=3OO~

DIMENSION C A R D S ( J X I D I M 1 , l O ) DIMENSION S I N C D ~ I D I M 2 , 7 ~ , I P T R Q ~ I D I M l , 4 ~ ~ I P T R T ~ I D I M l ~ Q ~ ~ N U M B E R ~ Q ~ DIMENSION I G R I D S ~ I D I M 1 . 2 ~ , C N T R O I D ~ 3 ~ , V E C T l ~ 3 ~ ~ V E C T 2 ~ 3 ~ ~ U N O R M ~ 3 ~ DIMENSION ARE~4),QFACTOR(IDIM1,4~~TFACTOR(IDIMl,4)

DIMENSION BFACTOR~IDIM1,2).1DS(IDIMl),XAX~3~~VECT3~3~ DIMENSION ISINCDC I D I M 2 ) INTEGER 0

CHARACTER A S C * 8 . C A R D S * 8 , B A R S ~ 8 . P L U S ~ 8 , S I N N A M E * 8 , T I M E ~ 8 EQUIVALENCE(SINCD(1,l~~ISINCD~l)) DATA BAR/lCRAP 1 8

DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA I D 1 M = l N = l 0=1

DIMENSION G R I D S ( I D I M l ~ 5 ) ~ I Q U A D S ~ I D I M l r 6 ) . I T R I A S ~ I D I M l ~ 5 ~

DIMENSION T ~ 4 ~ ~ P L U S ~ I D I M 1 ~ 7 ~ ~ B A R S ~ I D I M 1 , 9 ~ . Z A X ~ 3 ~ ~ Y A X ~ 3 ~ ~ D E L T ~ 4 ~ DIMENSION I P T R A ( I D I M 1 ~ 2 ) ~ I P T R B ( I D I M l ~ 2 ~ ~ A F A C T O R ( I D I M l ~ Z ~

CHARACTER BARr8,BEAM*8,QUAD4*S,QUAD8*8,TRIA3~8,TRIA6*8,GRID*8

---.. BEAM/ CB EAM l/

QUAD4/1CQUAD4 l/

QUADS/'CQUADS 1 1

T R I A 3/ CTR I A 3 * / T R I A 6 / ' C T R I A 6 G R I D / * G R I D l/

NASTDECK/ 30 / I N S I N D A / 2 5 / I S C R T C H l / 50 / ISCRTCH2/ 6 0 I S C R T C H U 90 / IGRDHLD/ 80 / IOCHECK/ 1 9 / INASSUB/ 4 5 / INASTEMP/ 46 /

ORIGINAL PAGE IS aE POOR QUALITY

14

APPENDIX B

S N I P Opera t ions C h e c k l i s t - PC Vers ion

1 - P l a c e i n p u t NASTRAN B u l k Data Deck i n a f i l e named NASTRAN.CDS

2 - Place i n p u t thermal model r e s u l t s i n a f i l e named SINDA.CDS

3 - A d j u s t i n p u t parameters i n S N I P source code PARAMETER s tatements ( s e e appendix A >

4 - Compile source code

5 - L i n k and r u n S N I P code

6 - R e v i e w r e s u l t a n t node-element r e l a t i o n s h i p s i n S N I P o u t p u t f i l e named SNIPIO.CHK ( i f r e l a t i o n s h i p s are n o t acceptab le , r e v i e w and r e v i s e i n p u t s t o 1 , 2, and 3 above as a p p r o p r i a t e and r u n S N I P aga in )

7 - NASTRAN temperature l o a d cards are i n t h e S N I P o u t p u t f i l e named TMPTR.CDS and NASTRAN case c o n t r o l cards a r e i n t h e S N I P o u t p u t f i l e named SUBCASE.CDS

15

APPENDIX C

SNIP Sample Run Fi le - CRAY Version

JOB,JN=SNIPRUN T=lS,MFL=4OOOOO. ACCOUNT, AC-, APW ASSIGN, DN=NAsFIL E, D c = s i M : ASSIGN,DN=SINFILE,DC=SC,A=FT25. ASSIGN,DN=SCRTCHl,DC=SC.A=FTSD. ASSIGN, DN=SCRTCH2, DC=SC;A=FTiO 1 ASSIGN,DN=SCRTCH3,DC=SC,A=FT90. ASSIGN,DN=GRDHLD,DC=SC,A=FT80. ASSIGN,DN=IOCHK,DC=SC,A=FTl9. ASSIGN, DN=SUBCASE, DC=SC, A z F T 4 5 . ASSIGN, DN=TMPTR, DC=SC, A = F T 4 6 . COPYF, I=$IN,O=SUURCE, N F = l .

COPYF~I=$IN,O=SINFILE,NF=1~

CFT, I=SOURCE.

COPYF, I = $ I N , O = N A S F I L E , N F = l . REWIND, DN=SOURCE.

LDR. DISPOSE,DN=IOCHK,DC=ST. DISPOSE,DN=SUBCASE,DC=ST. DISPOSE,DN=TMPTR,DC=ST.

\

/EOF

/EOF

/ EOF

CRAY Control Statements Fi 1 e

I I n p u t NASTRAN Bulk Data deck goes here

I 1 I n p u t Thermal Model resul ts f i l e goes here

ORIGINAL PAGE IS OF POOR QUALITY

16

APPENDIX D

S N I P Opera t i ons C h e c k l i s t - CRAY Vers ion

1 - A d j u s t i n p u t parameters i n S N I P source code PARAMETER s tatements ( s e e

2 - Crea te CRAY j o b C o n t r o l Statements f i l e t h a t :

appendix A)

( 1 ) ASSIGNS a p p r o p r i a t e FORTRAN l o g i c a l u n i t numbers t o the f o l l o w i n g

( 1 ) i n p u t NASTRAN Bulk Data f i l e ( u n i t = NASTDECK) (2) i n p u t thermal model r e s u l t s f i l e ( u n i t = I N S I N D A ) (3-6) f o u r i n t e r m e d i a t e da ta s to rage f i l e s ( u n i t = I S C R T C H I ,

( 7 ) o u t p u t node-element r e l a t i o n s h i p s f i l e ( u n i t = IOCHECK) ( 8 ) o u t p u t NASTRAN tempera ture l oad cards ( u n i t = INASTEMP) ( 9 ) o u t p u t NASTRAN case c o n t r o l cards ( u n i t = INASSUB)

(2) COPYs i n p u t f i l e s (NASTRAN model and thermal model r e s u l t s )

( 3 ) Compiles and runs t h e S N I P source code ( 4 ) DISPOSES t h e o u t p u t f i l e s from the CRAY t o t h e user ( s e e apendix C)

f i l e s :

ISCRTCH2, ISCRTCH3, and IGRDHLD)

i n t o a p p r o p r i a t e CRAY f i l e s

3 - Combine CRAY j o b C o n t r o l Statements f i l e , S N I P source code f i l e , i n p u t NASTRAN Bu ld Data f i l e , and i n p u t thermal model r e s u l t s f i l e i n t o a CRAY f i l e

4 - Submit CRAY r u n f i l e t o CRAY f o r ba tch p rocess ing

5 - Review r e s u l t i n g node-element r e l a t i o n s h i p s i n the a p p r o p r i a t e o u t p u t f i l e ( i f r e l a t i o n s h i p s a r e n o t acceptab le , r e v i e w and r e v i s e i n p u t parameters a n d l o r i n p u t da ta as a p p r o p r i a t e and r u n S N I P aga in )

17

REFERENCES

1 . McCormick, C.W., ed. : MSCINASTRAN U s e r ' s Manual, V e r s i o n 63, MacNeal- Schwendler Corp., 1983.

2. CRAY-OS Vers ion 1 Reference Manual SR-0011, R e v i s i o n L, CRAY Research I n c . , M inneapo l i s , MN, J u l y 1983.

3. S te inbach , R .E . ; and Winegar, S .R . : I n t e r d i s c i p l i n a r y Design A n a l y s i s of P r e c i s i o n Spacecraf t Antenna. 2 6 t h S t r u c t u r e s , S t r u c t u r a l Dynamics, and M a t e r i a l s Conference, P a r t 1 , 1985, pp. 704-712.

18

TABLE I. - CASE 1 THERMAL MODEL RESULT INPUT F I L E

CASE 1 8:00 9 1,25 . ,0 .0 ,1 .67 ,1 .67 ,0 .0 ,0 .0 2,50.,0.0,5.0,1.67,0.0,0.0 3,75.,0.0,8.33,1.67,0.0,0.0 4,50.,0.0,1.67,5.0,0.0,0.0

6,100.,0.0,8.33,5.0,0.0,0.0 7,75.,0.0,1.67,8.33,0.0,0.0 8,100.,0.0,5.0,8.33,0.0,0.0 9,125.,0.0,8.33,8.33,0.0~0.0

5,75.,0.0,5.0,5.0,0.0~0.0

19

21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

4 4 5 5 5 6 6 6 0 0 4 4 5 5 5 6 6 6 0 0 4 4 5 5 5 6 6 6 0 0

0.342 0.253 0.149 0.196 0.193 0.131 0.185 0.200 0.000 0.000 0.533 0.549 0.196 0.277 0.358 0.177 0.248 0.334 0.000 0.000 0.706 0.843 0.193 0.358 0.599 0.147 0.298 0.509 0.000 0.000

0 0 4 4 4 5 5 5 6 6 0 0 4 4 4 5 5 5 6 6 0 0 4 4 4 5 5 5 6 6

0.000 0.000 0 .200 0 .185 0.131 0.193 0 .196 0.149 0.253 0 .342 0.000 0.000 0 .334 0 .248 0 .177 0 .358 0 .277 0 .196 0 .549 0 .533 0.000 0.000 0 .509 0 .298 0 .147 0 .599 0 .358 0 .193 0 .843 0 .706

0 0 1 1 1 2 2 2 3 3 0 0 1 1 1 2 2 2 3 3 0 0 1 1 1 2 2 2 3 3

0.000 0.000 0 .450 0.285 0.167 0 .509 0 .334 0 . 2 0 0 0.747 0 .658 0.000 0.000 0.285 0 .227 0 .168 0.298 0 .248 0.185 0 .451 0 .467 0.000 0.000 0 .167 0 .168 0 .106 0 .147 0.177 0 .131 0.157 0 .294

1 1 2 2 2 3 3 3 0 0 1 1 2 2 2 3 3 3 0 0 1 1 2 2 2 3 3 3 0 0

0 .658 0 .747 0 .200 0 .334 0 .509 0 .167 0 .285 0 .450 0.000 0.000 0 .467 0 .451 0 .185 0 .248 0 .298 0 .168 0 .227 0 .285 0.000 0.000 0 .294 0 .157 0 .131 0 .177 0 .147 0 .106 0 .168 0 .167 0.000 0.000

20

TABLE 111. - CASE 1 NODE-ELEMENT RELATIONSHIPS (ALWDR = 2.2 i n . )

QUAD SlNDA W.F. SINDA W.F. SINDA W.F. SINDA W.F. ELEMENT NODE 1 1 NODE2 2 NODE3 3 NODE4 4 ........................

21 0 0.000 22 0 0.000 23 0 0.000 24 0 0.000 25 0 0.000 26 0 0.000 27 0 0.000 28 0 0.000 29 0 0.000 3 0 0 0.000 31 4 0 .533 32 4 0 .549 33 0 0.000 34 5 1 .ooo 35 5 0 .545 36 0 0.000 37 0 0.000 38 6 0 .540 39 0 0.000 40 0 0.000 41 4 1 .000 42 4 1 .ooo 43 0 0.000 44 5 0.545 45 5 1.000 46 0 0.000 47 6 0 .455 48 6 1 .000 49 0 0.000 50 0 0.000

0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 5 5 0 6 6 0 0 4 4 0 5 5 0 6 6

------- 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.540 0.000 0.000 0.545 1 .ooo 0.000 0.549 0.533 0.000 0.000 1 .ooo 0.455 0.000 1 .ooo 0.545 0.000 1 .ooo 1 .ooo

-------- 0 0 1 1 0 2 2 0 3 3 0 0 1 0 0 2 0 0 3 3 0 0 0 0 0 0 0 0 0 0

------- 0.000 0.000 1 .ooo 0 .460 0.000 1 .ooo 0 .540 0.000 1 .ooo 1 .ooo 0.000 0.000 0 .460 0.000 0.000 0 . 4 5 5 0.000 0.000 0 .451 0 .467 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

I - - - - - - - - - - - - - - - - - - _ - -

1 1 .ooo 1 1 .ooo 0 0.000 2 0 . 5 4 0 2 1 .ooo 0 0.000 3 0 . 4 6 0 3 1 .ooo 0 0.000 0 0.000 1 0 .467 1 0 .451 0 0.000 0 0.000 2 0 .455 0 0.000 0 0.000 3 0 .460 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

21

TABLE I V . - CASE 4 BAR ELEMENT NODE-ELEMENT RELATIONSHIPS

BEAM END: SINDA W.F. SlNDA W.F. END: SlNDA W.F. SINDA W.F ELEMENT A NODE1 1 NODE2 2 B NODE 1 1 NODE2 2

501 502 503 504 505 506 507 508 509 510 51 1 512 513 514 515 516 517 518 519 520

0 0.000 0 0.000

1001 0.901 1001 0.601 1001 0 .300 1002 1.000 1002 0 .700 1002 0 .399 1002 0.099 1003 1.000 1011 1.000 1011 0.800 1011 0.600 1011 0.400 1011 0.200 1012 1.000 1012 0 .800 1012 0 .600 1012 0.400 1012 0.200

TABLE V .

1001 1 .000 1001 1.000 1002 0 .099 1002 0 .399 1002 0 .700 1003 0.000 1003 0 .300 1003 0 .601 1003 0 .901

0 0.000 1012 0.000 1012 0.200 1012 0.400 1012 0 .600 1012 0 .800 1013 0.000 1013 0 .200 1013 0 .400 1013 0 .600 1013 0 .800

- CASE 4 BAR ELEMENT

0 0.000 001 0 .901 001 0 .601 001 0 .300 002 1 .ooo 002 0 .700 002 0 . 3 9 9 002 0 .099 003 1 .OOO

1003 101 1 101 1 101 1 101 1 1012 1012 1012 1012 1012 1013

TEMPERATURES

1 .ooo 0 . 8 0 0 0 .600 0 .400 0 .200 1 .ooo 0 .800 0.600 0 .400 0 .200 1 .ooo

1001 1 . 0 0 G 002 0.099 002 0.396 002 0 . 7 O C 003 0 . O O C 003 0 . 3 O C 003 0.601 003 0 .901 0 0.ooc 0 0.ooc

1012 0.2oc 1012 0.4OC 1012 0.600 1012 0.8OC 1013 0.000 1013 0.2OC 1013 0 . 4 0 G 1013 0.60G 1013 0.8OC

0 0.ooc

ELEMENT TEMPERATURE,END A(X, in ) TEMPERATURE,END B ' ( X m a x )

501 502 503 504 505 506 507 508 509 510 51 1 512 513 514 515 516 517 518 519 520

-20. -20. -15.

0. 15. 30 . 45. 60 . 75 . 80.

-15. -5.

5 . 15. 25. 35 . 45 . 55. 65 . 75 .

-20. -15.

0. 15. 30 . 45 . 60 . 7 5 . 80. 80 . -5.

5 . 15. 25 . 35. 45 . 55 . 65. 75 . 85 .

22

I GET NEW INPUT I

NO NO

GO TO HEIGHT CALCULATION

GlCN SEGMENT

STORE NODE NUMBER AND CHARACTER 1 S T I C DISTANCE I N L IST FOR RE- GION SEGMENT

FIGURE 1. - CORRELATION ROUTINE LOGIC.

23

\ Z *ALWDTH

RADII TO TOP AND BOTTOM EDGES OF REGION. ALWDR

FIGURE 2. - QUALIFICATION REGION FOR THE SHADED ELEMENT OF THE PLATE ELENENTS SHOWN.

Lx FIGURE 3. - BAR ELEMENT COORDINATE SYSTEM ( X ALONG ELEENT AXIS).

r + ALWDR2 -I

1 // ALWDY & k R AND Ern ELEMENT

QUALIFICATION REGION SEGMENTS (2)

FIGURE 4. - QUALIFICATION REGION FOR END B OF THE CENTER BAR ELEMENT SHOWN.

PLATE ELEMENTS (VIEWED EDGE ON)

-L--- NVAR3 -PLATE ELEENT

QUAL I F ICATION REG I ON c3 - BAR ELEMENT (VIEWED END ON)

I \\ OFFSET -

NASTRAN BAR AND NASTRAN PLATE INPUT THERMAL \

-BAR ELERENT QUALIFICATION AND SHELL NODE NUMBERS BEAM ELEMENT REGION ELEMENT NUHLERS NUMBERS

FIGURE 5. - OVERLAPPING RUALIFICATION REGIONS. FIGURE 6. - NUERICAL CODING SCHEw-

24

CORRELATE

NASTRAN PLATE

CORRELATE

INPUT THERMAL NASTRAN BAR AND - - . . . -. -. .-

r P L A T E ELEENTS (ELEMENT / NUMEiERS < NVARZ)

FBEM ELEENTS (ELEMEN1 /

AND SHELL NODE NUMBERS &AN tLUZNT E L W N T N W R S NUneERS

FIGURE 7. - POTENTIAL SETUP OF N W R I C A L CODING SCHEE. FIGURE 8. - EM ELEENTS SUPPORTING PLATE ELEMENT STRUCTURE.

QUAD SlNDA W . F . SlNDA W . F . S lNDA W . F . S lNDA W . F . ELEMENT MODE1 1 MODE2 2 MODE3 3 MODE4 4 ...........................................................................

1 0 O.OD0 0 0.000 0 0.000 1 1.000 2 1 1.000 0 0.000 0 0.000 0 0.000 3 2 0.342 1 0.658 0 0.000 0 0.000 4 2 0.533 1 0.487 0 0.000 0 0.000 5 2 0.706 1 0.294 0 0.000 0 0.000 6 3 0.294 2 0 . 7 0 6 0 0.000 0 0.000 7 3 0.467 2 0.533 0 0.000 0 0.000 8 3 0.658 2 0.342 0 0.000 0 0.000 9 0 0.000 3 1.000 0 0.000 0 0.000

10 0 0.000 3 1.000 0 0.000 0 0.000 11 1 1.000 0 0.000 0 0.000 0 0.000 12 1 1 .ooo 0 0.000 0 0.000 0 0.000

0 0.000 13 2 0.253 1 0,747 0 0.000 14 2 0.549 1 0.451 0 0.000 0 0.000 15 2 0.843 1 0.157 0 0.000 0 0.000

BEAM END: SlNOA W . F . SINOA W . F . END: SlNOA W . F . SlNOA W . F . ELEMENT A W O E 1 1 WOE2 2 B NODE1 1 W O E 2 2 _______-________________________________--_----------------~~--------------

1 .ooo 0 0.000 1001 1.000 50 1 502 503 504 505 506 507 508 509 510 51 1 512 513 514 515 516 517 518 519 520

0 0.000 1001 0 0.000 1001

1001 0.901 1002 1001 0.601 1002 1001 0.300 1002 1002 1 .OOO 1003 1002 0.700 1003 1002 0.399 1003 1002 0.099 1003 1003 1.000 0 1011 1.000 1012 1011 0.600 1012 1011 0.600 1012 1011 0.400 1012 1011 0.200 1012 1012 1.000 1013 1012 0.800 1013 1012 0.800 1013 1012 0.400 1013 1012 0.200 1013

1.000 0.099 0.399 0.700 0.000 0.300 0.601 0.901 0.000 0.000 0.200 0.400 0.600 0.800 0.000 0.200 0.400 0.600 0,800

1001 1001 1001 1002 1002 1002 1002 1003 1003 101 1 101 1 101 1 101 1 1012 1012 1012 1012 1012 1013

0.901 0.601 0.300 1.000 0.700 0.399 0,099 1.000 1.000 0.800 0.600 0.400 0.200 1.000 0.800 0.600 0.400 0.200 1.000

1002 1002 1002 1003 1003 1003 1003

0 0

1012 1012 1012 1012 1013 1013 1013 1013 1013

0

0.099 0.399 0.700 0.000 0.300 0.601 0.901 0.000 0.000 0.200 0.400 0.600 0.800 0 000 0 200 0.400 0.600 0.800 0.000

FIGURE 9. - NODE-ELEMENT CORRELATION AND WEIGHTING FACTOR F I L E LISTING.

25

i 10

9

8

7

$ 6 ~ 51 52

4

3

2

1

0 1

3 5 E 41 42

RECORD - 1

2

3 11

5

0

b

N+3 -

DATA DESCRIPTION (FORTRAN FORMAT)

MODEL OR RUN NAME (A81 TIRE (OF DAY) ASSOCIATED WITH RUN (A81 NUHBER OF NODES I N MODEL - N (A18)

NODE # , AVERAGE TEMPERATURE AT NODE,

TEMPERATURE GRADIENT I N ELEMENT 2 DIRECTION AT NODE,

NODE X COORDINATE. NODE Y COORDINATE, NODE 2 COORDINATE.

TWERATURE GRADIENT I N ELEMENT Y DIRECTION AT NODE FREE

REPEAT FOR EACH THERMAL LOAD CASE.

FIGURE 10. - SINDA (THERMAL MODEL RESULT) INPUT FILE AND FORMAT.

94 I 95 I 96 I 97 I 9 8

84 85 86 87 88

74 75 76 77 78

64 I 65 1 66 I 67 I 6 8

2J2.lLw 1 4 5 6 7

1 9 1 201

2.w ‘X L 9 10

INCHES

FIGURE 11. - CASE 1. 2 NASTRAN ELEMENT GRID.

Y

--X

FIGURE 12. - CASE 1. 2 SINDA NODE GRID.

26

Y

750 1000

50' 750

25' 50'

t 125'

1000

750

FIGURE 13 . - CASE 1 SINDA INPUT TEMPERATURE PATTERN.

- I I - I V = QUALIFICATION REGION QUADRANTS 1 - 4

R2 AND R3 = X-LARGE

I I V I FIGRUE 15. - NODE-ELEMENT PHYSICAL RELATIONSHIPS FOR ELEMENT 21.

Y

FIGURE 14. - CASE 1 RESULTING NASTRAN TEMPERATURE PATTERN. DEGREES (ALWDR = 10.0").

i

FIGURE 16. - CASE 1 RESULTING NASTRAN TEMPERATURE PATTERN, DEGREES (ALWDR = 2 . 2 " ) .

27

Y

t Y

r n

FIGURE 17 . - CASE 2 SINDA INPUT TEWPERATURE PATTERN.

r T = 25' r T = 50' ,--T = 75' /

/

\<' \ 25' \

\

\

\

'\ \

\

00

I

1/. y 50'

I I

I I

I 50'

I I I I I I 50'

--X FIGURE 19. - CASE 2 ISOTHERMAL LINES OVERLAYED ON SINDA GRID.

28

- n

FIGURE 18. - CASE 2 RESULTING NASTRAN TEMPERATURE PATTERN, DE- GREES.

fly 501 502 503 504 505 506 507 508 509 510

- - -

FIGURE 20. - CASE 3 BAR ELEKNTS (NURERED).

+ - BAR THERMAL NODES i 25'

-200

00

25'

80'

I AX

FIGURE 21. - CASE 3 SINDA INPUT TEMPERATURE PATTERN.

2

NODE 1011 7 f '

FIGURE 22. - CASE 4 BAR ELEENTS (NUMBERED).

FIGURE 23. - QUALIFICATION REGION FOR X = 2.0" END OF ELEMENT 512 (CASE 4 ) .

29

NASA 1. Report No.

NASA TM-100158

Report Documentation Page 2. Government Accession No.

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No of pages

U n c l a s s i f i e d U n c l a s s i f i e d 30

7. Author($

Steven R . Winegar

22. Price'

A03

9. Performing Organization Name and Address

N a t i o n a l Aeronaut ics and Space A d m i n i s t r a t i o n Lewis Research Center Cleveland, Ohio 44135

N a t i o n a l Aeronaut ics and Space A d m i n i s t r a t i o n Washington, D.C. 20546

12. Sponsoring Agency Name and Address

15. Supplementary Notes

3. Recipient's Catalog No.

5. Report Date

August 1987

6. Performing Organization Code

481 -50-32

8. Performing Organization Report No.

E-3720

10. Work Unit No.

11. Contract or Grant No.

13. Type of Report and Period Covered

7 ec hn i ca 1 Memorandum

14. Sponsoring Agency Code

16. Abstract

l h e t a s k o f c o n v e r t i n g SINDA f i n i t e d i f f e r e n c e the rma l model tempera ture r e s u l t s i n t o NASlRAN f i n i t e element model thermal loads can be v e r y l a b o r i n t e n s i v e i f t h e r e i s n o t one node-to-one element, o r sys temat i c node- to - element, c o r r e l a t i o n between models. Th i s paper desc r ibes t h e S INDA-NASlRAN I n t e r f a c i n g Program ( S N I P ) , a F O R l R A N computer code t h a t generates N A S l R A N s t r u c t u r a l model thermal l o a d cards g i ven SINDA ( o r s i m i l a r thermal model) t e m - p e r a t u r e r e s u l t s and thermal model geometr ic da ta . S N I P generates NASTRAN thermal l oad cards f o r NASlRAN p l a t e , s h e l l , ba r , and beam elements. The paper d e s c r i b e s the i n t e r f a c i n g procedures used by SNIP, and d iscusses set -up and o p e r a t i o n o f t h e program. t h e program and show i t s ' performance under a v a r i e t y o f c o n d i t i o n s . p r o v i d e s t r u c t u r a l model t he rma l loads t h a t a c c u r a t e l y r e f l e c t thermal model r e s u l t s w h i l e reducing t h e t i m e r e q u i r e d t o i n t e r f a c e the rma l and s t r u c t u r a l models when compared t o o t h e r methods.

Sample cases a r e i n c l u d e d t o demonstrate use o f S N I P can

17. Key Words (Suggested by Author($)

N A S l RAN SINDA l h e r m a l d i s t o r t i o n l h e r m a l de format ion

18. Distribution Statement

U n c l a s s i f i e d - u n l i m i t e d STAR Category 39

NASA FORM 1626 OCT 86 'For sale by the National Technical Information Service, Springfield. Virginia 221 61